Upon injury or infection, the body releases chemicals that trigger tissue repair and pathogen clearance. Because the medical community needs new therapeutic leads in this era of growing antibiotic resistance, identifying these molecules is a high priority. Dalli et al. looked for these factors in mice infected with self-resolving Escherichia coli, in human breast milk, and in regenerating planaria. They identified two related molecules, conserved across these organisms, which promoted pathogen clearance, reduced inflammation, and accelerated tissue regeneration. Scientists will need to carry out further studies to determine whether these chemicals have similar properties in humans.